1. Field of the Invention
The present invention relates to a network system including a network device that permits a user to use functions according to permission, and an authentication server capable of communicating with the network device; a use permission determining method for use in the network device; the network device; and a computer-readable recording medium having a program embodied therein for controlling the network device with use of a computer.
2. Description of the Related Art
There have been digital multifunction devices (MFP) that can limit available functions to users on a per-user basis or a per-group basis. These devices identify the users based on, for example, user codes entered by the users on operations panels of the devices or ID cards of the users, and allow the users to use the functions within the scope of permission granted to the users.
In such devices, it is possible to limit colors in copying, or functions in fax transmission, printing, and scanning on a per-user basis. It is also possible to limit the number of sheets on a per-group basis according to a calculated number of sheets used by each group so as to prevent excessive use.
Examples of these types of devices are disclosed, for example, in Patent Documents 1-3.
[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-178567
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2002-240398
[Patent Document 3] Japanese Patent Laid-Open Publication No. 10-58796
Devices disclosed in Patent Documents 1-3 are configured to perform user identification (authentication) by themselves. Meanwhile, there is disclosed a system, e.g., in Patent Document 4, that includes a directory server for centrally managing user information and information indicating permission for use of the network devices granted to individual users. In this system, the network devices determine whether use permission is granted to a user by using an authentication function of the directory server.
[Patent Document 4] Japanese Patent Laid-Open Publication No. 2002-202945
According to Patent Documents 1-3, a network device for providing their functions to users performs authentication. Therefore, if plural network devices are used in a user environment, registration or deletion of information such as a user ID and a password need to be carried out in each of the network devices so as to add or delete a user, resulting in troublesome setting operations.
Such a problem may be solved by providing a server as disclosed in Patent Document 4 that centrally manages user information for network login or the like, and information about permission for use of individual devices. In implementation of such a central information management system by a server, a database describing user access to each network device needs to be created. However, creating such a database requires knowledge in networking as well as being troublesome work.